Gregor



C. G. MAcGREGOR.

FLYING BOAT HULL.

APPLICATION FILED SEPT. 14. 1911.

Patented Supt. 23, 1919.

fln'uc mfo'c CHARLESGJMACGREGOR UNITED STATES PATENT OFFICE.

CHARLES GORDON MAGGREGOR, OF BUFFALO, NEW YORK, ASSIGNOR TO CURTISS AEROPLANE AND MOTOR CORPORATION, A CORPORATION OF NEW YORK.

FLYING-BOAT HULL.

Specification of Letters Patent.

Patented Sept. 23, 1919.

To all whom it may concern:

Be it known that I, CHARLES G. MAG- GREGOR, a citizen of the United States, residing at Bufialo, in the county of Erie and State of New York, have invented certain new. and useful Improvements in Flying- Boat Hulls, of which the following is a specification.

My invention relates to hydroplane boats of the type commonly used in connection with hydroaeroplanes and flying boats. It is characterized principally by a continuation or prolongation of the fin excrescencies (which distinguish Curtissdiying boats) rearwardly beyond the line of demarcation between the fore body of the hull and the tail. This line of demarcation is usually indicated by a transverse break in the longitudinal continuity of the hull bottom commonly called'a step. (If a plural or multiple number of steps are provided that portion of the hull aft of its lowermost point may be said to constitute the tail).

By extending the fin excrescencies rearwardly beyond the step, it is proposed to materially increase and at the same time longitudinally distribute the buoyancy in such manner that the center of buoyancy lies more nearly amidships with the result that the craft is floatedhigher in the water. The seaworthiness of the hull is also improved and the trim materially bettered. In the manufacture of finned boat hulls as at present constructed, difiiculty is experienced in construction work by reason of the abrupt termination of the hydroplane bottom of the boat in transverse alinement with the step. Such construction necessitates a discontlnuance of the fin edge stringers and other hull parts at the very pointwhere the greatest strength is needed. A continuation of these essential parts beyond the step without interrupting the continuity of the bottom foundation increases greatly the strength of the hull both longitudinally and transversely and at the same time simplifies construction to a very considerable extent. Moreover, the extended fins tend to resist rolling action. In addition a plural number of steps may be provided in the hull bottom with a minimum of structural changes. Better streamlines are also produced. 1

In the drawings, wherein like characters of reference designate like or corresponding parts;

Figure 1 is a plan view of a flying boat hull equipped with fins constructed to bridge the step;

Fig. 2 is a side elevation of the hull as illustrated in Fig. 1, and

Figs. 3, 4, and 5 are sections respectively on the lines 3-3, H, and 5-5 of Fig. 2.

The fore body of the hull I have designated in its entirety as 10. It is provided with a hydroplaning bottom 11 of V-torm in transverse section and with a relatively blunt nose 12. The tail 13 of the hull is in reality an integral part of the fore body 10 being merely a continuation thereof rearwardly as shown. The bottom let of the tail portion of the hull may be said to extend rearwardly and slightly upwardly from its point of inception at the step 15. This step affords a line of demarcation between the fore body 10 and tail 13 and in flying boats approximately underlies the center of gravity of the machine. Ordinarlly but one step is provided. Two or more steps, however, may be equally as well used. The function of the step or steps is to decrease suction and skin friction while hydroplaning and to ermit ofthe proper displriiblution of more or less air beneath the Fin excrescencies 16 are provided at opposlte sides of the hull to augment the hydroplaning bottom 11 and add buoyancy to the craft. These fins in machines of this type heretofore constructed have terminated rearwardly squarely in alinement with the step 15. In none of these machines have the fins been continued beyond the step. A continuation of the fins 16 beyond the step adds greatly to the seaworthiness and structural strength of the hull without increasmg either the skin friction while hydroplaning or the head resistance while in the air. The fins 16 as shown, emanate from a point in the vicinity of the bow end of the hull and gradually widen out to a point of maximum width in the vicinity of the step. From said point aft the width of the fins decreases gradually; the fins at their rear extremities merging into the sides of the hull at a point considerably aft of the step, preferably approximately three-fifths astern of the full length of the hull. The

the step from the bow as heretofore.

fins may be thus described as bridging the step. Their transverse and longitudinal section is such that even better streamlines are produced than heretofore. This is possible because of their horizontal flatness, as it were, rather than their inclination toward Where more than one step is provided the fins should continue rearwardly from their points of inception beyond at least one of the steps and where more than one step lies in advance of the rearward termination of the hydroplaning bottom, the fins should bridge said oint. The fins thus extended afford a goo protection for the main hull and insure the safety of the boat against sinking when divided longitudinally into. water-tight compartments should one or both fins be fractured or from other cause spring a leak. Still another advantage obtained through such a fin construction is the better foundation afforded for the effective bracing of the conventional stub Wings found in most Ourtissflying boats. Obviously, a brace might beextended diagonally inwardly from the rear wing beam of the stub wlng to the fin at each side of tghe hull in much the same manner as the race arrangement which at present characterizes the forward wing beam. The principal advantages, however, are as heretofore pointed out, i. e., the added buoyancy; the uniform longitudinal buoyancy distribution, the simplified construction and the bringing of the center of buoyancy more nearly amidships.

various forms.

The fin excrescencies although disclosed as of decreasing Width both fore and aft from a point in transverse alinement with the step may obviously be made or constructed in Also, they may be continued rearwardly to a point adjacent the stern post of the hull or continued only slightly rearwardly beyond the step. What I emphasize is the continuation of the fins rear- Wardly beyond the step or rather beyond that point in the hull bottom rearwardly terminating its hydroplaning surface.

What is claimed is: I 1. In a hull for flying boats, a bottom surface having. its longitudinal continuity surface having its longitudinal continuity.

interrupted transversely by a rearwardly facing step, and longitudinally streamlined fin excrescencies formed in lateral continuation of said bottom both in advance 0 and aft of said step.

4. In a hull for flying boats, a bottom surface having its longitudinal continuity transversely interrupted by a rearwardly facing step, and lateral fin excrescencies arranged to augment said bottom surface, the

width of said excrescencies decreasing. grad-- ually both fore and aft from a point adjacent said step.

' In testimony whereof I hereunto aflix my signature.

CHARLES sorrow Manson.- 

